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From:   Uladzislau Rezki <urezki@gmail.com>
Date:   Wed, 15 Jul 2020 21:36:57 +0200
To:     Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc:     Uladzislau Rezki <urezki@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>, RCU <rcu@vger.kernel.org>,
        linux-mm@kvack.org, "Paul E . McKenney" <paulmck@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Theodore Y . Ts'o" <tytso@mit.edu>,
        Matthew Wilcox <willy@infradead.org>,
        Joel Fernandes <joel@joelfernandes.org>,
        Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Subject: Re: [PATCH 1/1] rcu/tree: Drop the lock before entering to page
 allocator
Message-ID: <20200715193657.GB26938@pc636>
References: <20200715183537.4010-1-urezki@gmail.com>
 <20200715185628.7b4k3o5efp4gnbla@linutronix.de>
 <20200715190243.GA26735@pc636>
 <20200715193250.axntj7jdt6bw52dr@linutronix.de>
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On Wed, Jul 15, 2020 at 09:32:50PM +0200, Sebastian Andrzej Siewior wrote:
> On 2020-07-15 21:02:43 [+0200], Uladzislau Rezki wrote:
> > 
> > <snip>
> >     spin_lock();
> >     __get_free_page(GFP_NOWAIT | __GFP_NOWARN);
> >     spin_unlock();
> > <snip>
> > 
> > Also, please note we do it for regular kernel.
> 
> ach right okay then.
> 
> > >
> > > What happened to the part where I asked for a spinlock_t?
> > > 
> > What do you mean?
> 
> Please drop that raw_spinlock_t for the kfree_rcu() based locking and
> use just a plain spinlock_t for the locking. Then you can keep the same
> code flow for RT and !RT without any special cases and everything.
> 
Ahhh... That i see :)

I guess it is up to Paul. I wrote my thoughts. I have only one concern
that i explained in my previous mails.

Thank you, Sebastian, for your comments!

--
Vlad Rezki